The Bernardo fire, the first of a spate of wildfires to erupt in San Diego County last week, is 100 percent contained, Cal Fire reported Saturday night.
Sparked on Tuesday by what Cal Fire called "powered equipment from a construction project," the blaze blackened nearly 1,600 acres from Rancho Peñasquitos to Rancho Santa Fe and prompted the evacuation of about 5,000 homes.
No structures were damaged in the fire, and no injuries occurred, according to Cal Fire.
The blaze began at 11 a.m. Tuesday off Nighthawk Lane in 4S Ranch amid hot, dry and gusty conditions and was pushed to the west and north by stiff Santa Ana winds.
Investigators determined that the Bernardo fire began as a crew was excavating trenches to test soil at the work site near Del Norte High School.
After digging and then covering one of the troughs, they started moving to the next excavation location, according to the San Diego Fire-Rescue Department. The workers then noticed flames spreading rapidly through dry brush and tried in vain to extinguish them before fleeing for their own safety, officials said.
